Displaying publications 21 - 40 of 67 in total

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  1. Fulltext Expression of Endogenous Angiotensin-Converting Enzyme 2 in Human Induced Pluripotent Stem Cell-Derived Retinal Organoids
    Ahmad Mulyadi Lai HI, Chou SJ, Chien Y, Tsai PH, Chien CS, Hsu CC, et al.
    Int J Mol Sci, 2021 Jan 28;22(3).
    PMID: 33525682 DOI: 10.3390/ijms22031320
    Angiotensin-converting enzyme 2 (ACE2) was identified as the main host cell receptor for the entry of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its subsequent infection. In some coronavirus disease 2019 (COVID-19) patients, it has been reported that the nervous tissues and the eyes were also affected. However, evidence supporting that the retina is a target tissue for SARS-CoV-2 infection is still lacking. This present study aimed to investigate whether ACE2 expression plays a role in human retinal neurons during SARS-CoV-2 infection. Human induced pluripotent stem cell (hiPSC)-derived retinal organoids and monolayer cultures derived from dissociated retinal organoids were generated. To validate the potential entry of SARS-CoV-2 infection in the retina, we showed that hiPSC-derived retinal organoids and monolayer cultures endogenously express ACE2 and transmembrane serine protease 2 (TMPRSS2) on the mRNA level. Immunofluorescence staining confirmed the protein expression of ACE2 and TMPRSS2 in retinal organoids and monolayer cultures. Furthermore, using the SARS-CoV-2 pseudovirus spike protein with GFP expression system, we found that retinal organoids and monolayer cultures can potentially be infected by the SARS-CoV-2 pseudovirus. Collectively, our findings highlighted the potential of iPSC-derived retinal organoids as the models for ACE2 receptor-based SARS-CoV-2 infection.
    Matched MeSH terms: Induced Pluripotent Stem Cells/cytology*; Induced Pluripotent Stem Cells/metabolism
  2. Fulltext Frequent co-expression of miRNA-5p and -3p species and cross-targeting in induced pluripotent stem cells
    Huang CJ, Nguyen PN, Choo KB, Sugii S, Wee K, Cheong SK, et al.
    Int J Med Sci, 2014;11(8):824-33.
    PMID: 24936146 DOI: 10.7150/ijms.8358
    A miRNA precursor generally gives rise to one major miRNA species derived from the 5' arm, and are called miRNA-5p. However, more recent studies have shown co-expression of miRNA-5p and -3p, albeit in different concentrations, in cancer cells targeting different sets of transcripts. Co-expression and regulation of the -5p and -3p miRNA species in stem cells, particularly in the reprogramming process, have not been studied.
    Matched MeSH terms: Induced Pluripotent Stem Cells/metabolism*
  3. Generation of a MLL-AF9-specific stem cell model of acute monocytic leukemia
    Chiew MY, Boo NY, Voon K, Cheong SK, Leong PP
    Leuk Lymphoma, 2017 01;58(1):162-170.
    PMID: 27185517
    Acute monocytic leukemia (AML-M5), a subtype of acute myeloid leukemia (AML), affects mostly young children and has poor prognosis. The mechanisms of treatment failure of AML-M5 are still unclear. In this study, we generated iPSC from THP-1 cells from a patient with AML-M5, using retroviruses encoding the pluripotency-associated genes (OCT3/4, SOX2, KLF4 and c-MYC). These AML-M5-derived iPSC showed features similar with those of human embryonic stem cells in terms of the morphology, gene expression, protein/antigen expression and differentiation capability. Parental-specific markers were down-regulated in these AML-M5-derived iPSCs. Expression of MLL-AF9 fusion gene (previously identified to be associated with pathogenesis of AML-M5) was observed in all iPSC clones as well as parental cells. We conclude that AML-M5-specific iPSC clones have been successfully developed. This disease model may provide a novel approach for future study of pathogenesis and therapeutic intervention of AML-M5.
    Matched MeSH terms: Induced Pluripotent Stem Cells/metabolism
  4. Generation of induced pluripotent stem cells by a polycistronic lentiviral vector in feeder- and serum- free defined culture
    Al Abbar A, Nordin N, Ghazalli N, Abdullah S
    Tissue Cell, 2018 Dec;55:13-24.
    PMID: 30503056 DOI: 10.1016/j.tice.2018.09.004
    Induced pluripotent stem cells (iPSCs) have great potentials for regenerative medicine. However, serious concerns such as the use of the viral-mediated reprogramming strategies and exposure of iPSCs to animal products from feeder cells and serum-containing medium have restricted the application of iPSCs in the clinics. Therefore, the generation of iPSCs with minimal viral integrations and in non-animal sourced and serum-free medium is necessary. In this report, a polycistronic lentiviral vector carrying Yamanaka's factors was used to reprogram mouse fibroblasts into iPSCs in feeder- and xeno-free culture environment. The generated iPSCs exhibited morphology and self-renewal properties of embryonic stem cells (ESCs), expression of specific pluripotent markers, and potentials to differentiate into the three-major distinct specialized germ layers in vitro. The iPSCs were also shown to have the potential to differentiate into neural precursor and neurons in culture, with greater than 95% expression of nestin, Pax6 and βIII-tubulin. This body of work describes an alternative method of generating iPSCs by using polycistronic lentiviral vector that may minimize the risks associated with viral vector-mediated reprogramming and animal derived products in the culture media.
    Matched MeSH terms: Induced Pluripotent Stem Cells/cytology*
  5. Generation of pluripotent stem cells without the use of genetic material
    Higuchi A, Ling QD, Kumar SS, Munusamy MA, Alarfaj AA, Chang Y, et al.
    Lab Invest, 2015 Jan;95(1):26-42.
    PMID: 25365202 DOI: 10.1038/labinvest.2014.132
    Induced pluripotent stem cells (iPSCs) provide a platform to obtain patient-specific cells for use as a cell source in regenerative medicine. Although iPSCs do not have the ethical concerns of embryonic stem cells, iPSCs have not been widely used in clinical applications, as they are generated by gene transduction. Recently, iPSCs have been generated without the use of genetic material. For example, protein-induced PSCs and chemically induced PSCs have been generated by the use of small and large (protein) molecules. Several epigenetic characteristics are important for cell differentiation; therefore, several small-molecule inhibitors of epigenetic-modifying enzymes, such as DNA methyltransferases, histone deacetylases, histone methyltransferases, and histone demethylases, are potential candidates for the reprogramming of somatic cells into iPSCs. In this review, we discuss what types of small chemical or large (protein) molecules could be used to replace the viral transduction of genes and/or genetic reprogramming to obtain human iPSCs.
    Matched MeSH terms: Pluripotent Stem Cells/cytology*
  6. Fulltext Generation of the induced pluripotent stem cell (hiPSC) line (JUFMDOi004-A) from a patient with hearing loss carrying GJB2 (p.V37I) mutation
    Fukunaga I, Shiga T, Chen C, Oe Y, Danzaki K, Ohta S, et al.
    Stem Cell Res, 2020 03;43:101674.
    PMID: 31926383 DOI: 10.1016/j.scr.2019.101674
    The gap junction beta-2 (GJB2) gene is the most common genetic cause of hereditary deafness worldwide. Especially, V37I mutation in GJB2 is most prevalent in Southeast Asia including Thailand, Malaysia, and Indonesia. Furthermore, it is the second most prevalent cause in Japan and China, and exhibits an audiometric phenotype of mild-to-moderate hearing loss. In this study, we generated induced pluripotent stem cells (iPSC) from peripheral blood mononuclear cells (PBMCs) of patient with homozygous V37I mutation. This iPSC line will be a powerful tool for investigating the pathogenesis and for developing a treatment for GJB2-related hearing loss.
    Matched MeSH terms: Induced Pluripotent Stem Cells/metabolism*
  7. Fulltext Germline TET2 loss of function causes childhood immunodeficiency and lymphoma
    Stremenova Spegarova J, Lawless D, Mohamad SMB, Engelhardt KR, Doody G, Shrimpton J, et al.
    Blood, 2020 Aug 27;136(9):1055-1066.
    PMID: 32518946 DOI: 10.1182/blood.2020005844
    Molecular dissection of inborn errors of immunity can help to elucidate the nonredundant functions of individual genes. We studied 3 children with an immune dysregulation syndrome of susceptibility to infection, lymphadenopathy, hepatosplenomegaly, developmental delay, autoimmunity, and lymphoma of B-cell (n = 2) or T-cell (n = 1) origin. All 3 showed early autologous T-cell reconstitution following allogeneic hematopoietic stem cell transplantation. By whole-exome sequencing, we identified rare homozygous germline missense or nonsense variants in a known epigenetic regulator of gene expression: ten-eleven translocation methylcytosine dioxygenase 2 (TET2). Mutated TET2 protein was absent or enzymatically defective for 5-hydroxymethylating activity, resulting in whole-blood DNA hypermethylation. Circulating T cells showed an abnormal immunophenotype including expanded double-negative, but depleted follicular helper, T-cell compartments and impaired Fas-dependent apoptosis in 2 of 3 patients. Moreover, TET2-deficient B cells showed defective class-switch recombination. The hematopoietic potential of patient-derived induced pluripotent stem cells was skewed toward the myeloid lineage. These are the first reported cases of autosomal-recessive germline TET2 deficiency in humans, causing clinically significant immunodeficiency and an autoimmune lymphoproliferative syndrome with marked predisposition to lymphoma. This disease phenotype demonstrates the broad role of TET2 within the human immune system.
    Matched MeSH terms: Induced Pluripotent Stem Cells/pathology
  8. Global search for right cell type as a treatment modality for cardiovascular disease
    Musa S, Xin LZ, Govindasamy V, Fuen FW, Kasim NH
    Expert Opin Biol Ther, 2014 Jan;14(1):63-73.
    PMID: 24191782 DOI: 10.1517/14712598.2014.858694
    Acute myocardial infarction is the primary cause of heart disease-related death in the world. Reperfusion therapy is currently the backbone of treatment for acute myocardial infarction albeit with many limitations. With the emergence of stem cells as potential therapeutic agents, attempts in using them to enhance cardiac function have increased exponentially. However, it has its own disadvantages, and we postulate that the primary drawback is choosing the right cell type and solving this may significantly contribute to ambitious goal of using stem cells in the regeneration medicine.
    Matched MeSH terms: Induced Pluripotent Stem Cells/transplantation*
  9. Highly potent stem cells from full-term amniotic fluid: A realistic perspective
    Hamid AA, Joharry MK, Mun-Fun H, Hamzah SN, Rejali Z, Yazid MN, et al.
    Reprod Biol, 2017 Mar;17(1):9-18.
    PMID: 28262444 DOI: 10.1016/j.repbio.2017.02.001
    Amniotic fluid (AF) is now known to harbor highly potent stem cells, making it an excellent source for cell therapy. However, most of the stem cells isolated are from AF of mid-term pregnancies in which the collection procedure involves an invasive technique termed amniocentesis. This has limited the access in getting the fluid as the technique imposes certain level of risks to the mother as well as to the fetus. Alternatively, getting AF from full-term pregnancies or during deliveries would be a better resolution. Unfortunately, very few studies have isolated stem cells from AF at this stage of gestation, the fluid that is merely discarded. The question remains whether full-term AF harbors stem cells of similar potency as of the stem cells of mid-term AF. Here, we aim to review the prospect of having this type of stem cells by first looking at the origin and contents of AF particularly during different gestation period. We will then discuss the possibility that the AF, at full term, contains a population of highly potent stem cells. These stem cells are distinct from, and probably more potent than the AF mesenchymal stem cells (AF-MSCs) isolated from full-term AF. By comparing the studies on stem cells isolated from mid-term versus full-term AF from various species, we intend to address the prospect of having highly potent amniotic fluid stem cells from AF of full-term pregnancies in human and animals.
    Matched MeSH terms: Pluripotent Stem Cells/cytology
  10. Human Pluripotent Stem Cell Culture on Polyvinyl Alcohol-Co-Itaconic Acid Hydrogels with Varying Stiffness Under Xeno-Free Conditions
    Sung TC, Li HF, Higuchi A, Ling QD, Yang JS, Tseng YC, et al.
    J Vis Exp, 2018 02 03.
    PMID: 29443075 DOI: 10.3791/57314
    The effect of physical cues, such as the stiffness of biomaterials on the proliferation and differentiation of stem cells, has been investigated by several researchers. However, most of these investigators have used polyacrylamide hydrogels for stem cell culture in their studies. Therefore, their results are controversial because those results might originate from the specific characteristics of the polyacrylamide and not from the physical cue (stiffness) of the biomaterials. Here, we describe a protocol for preparing hydrogels, which are not based on polyacrylamide, where various stem, cells including human embryonic stem (ES) cells and human induced pluripotent stem (iPS) cells, can be cultured. Hydrogels with varying stiffness were prepared from bioinert polyvinyl alcohol-co-itaconic acid (P-IA), with stiffness controlled by crosslinking degree by changing crosslinking time. The P-IA hydrogels grafted with and without oligopeptides derived from extracellular matrix were investigated as a future platform for stem cell culture and differentiation. The culture and passage of amniotic fluid stem cells, adipose-derived stem cells, human ES cells, and human iPS cells is described in detail here. The oligopeptide P-IA hydrogels showed superior performances, which were induced by their stiffness properties. This protocol reports the synthesis of the biomaterial, their surface manipulation, along with controlling the stiffness properties and finally, their impact on stem cell fate using xeno-free culture conditions. Based on recent studies, such modified substrates can act as future platforms to support and direct the fate of various stem cells line to different linkages; and further, regenerate and restore the functions of the lost organ or tissue.
    Matched MeSH terms: Pluripotent Stem Cells/cytology; Pluripotent Stem Cells/metabolism*; Induced Pluripotent Stem Cells/cytology
  11. Fulltext Human iPS-derived pre-epicardial cells direct cardiomyocyte aggregation expansion and organization in vitro
    Tan JJ, Guyette JP, Miki K, Xiao L, Kaur G, Wu T, et al.
    Nat Commun, 2021 08 17;12(1):4997.
    PMID: 34404774 DOI: 10.1038/s41467-021-24921-z
    Epicardial formation is necessary for normal myocardial morphogenesis. Here, we show that differentiating hiPSC-derived lateral plate mesoderm with BMP4, RA and VEGF (BVR) can generate a premature form of epicardial cells (termed pre-epicardial cells, PECs) expressing WT1, TBX18, SEMA3D, and SCX within 7 days. BVR stimulation after Wnt inhibition of LPM demonstrates co-differentiation and spatial organization of PECs and cardiomyocytes (CMs) in a single 2D culture. Co-culture consolidates CMs into dense aggregates, which then form a connected beating syncytium with enhanced contractility and calcium handling; while PECs become more mature with significant upregulation of UPK1B, ITGA4, and ALDH1A2 expressions. Our study also demonstrates that PECs secrete IGF2 and stimulate CM proliferation in co-culture. Three-dimensional PEC-CM spheroid co-cultures form outer smooth muscle cell layers on cardiac micro-tissues with organized internal luminal structures. These characteristics suggest PECs could play a key role in enhancing tissue organization within engineered cardiac constructs in vitro.
    Matched MeSH terms: Induced Pluripotent Stem Cells
  12. Impact of Three-Dimentional Culture Systems on Hepatic Differentiation of Puripotent Stem Cells and Beyond
    Ramasamy TS, Ong ALC, Cui W
    Adv Exp Med Biol, 2018 10 26;1077:41-66.
    PMID: 30357683 DOI: 10.1007/978-981-13-0947-2_4
    Generation of functional hepatocytes from human pluripotent stem cells (hPSCs) is a vital tool to produce large amounts of human hepatocytes, which hold a great promise for biomedical and regenerative medicine applications. Despite a tremendous progress in developing the differentiation protocols recapitulating the developmental signalling and stages, these resulting hepatocytes from hPSCs yet achieve maturation and functionality comparable to those primary hepatocytes. The absence of 3D milieu in the culture and differentiation of these hepatocytes may account for this, at least partly, thus developing an optimal 3D culture could be a step forward to achieve this aim. Hence, review focuses on current development of 3D culture systems for hepatic differentiation and maturation and the future perspectives of its application.
    Matched MeSH terms: Pluripotent Stem Cells/cytology*
  13. In vitro expression of erythropoietin by transfected human mesenchymal stromal cells
    Mok PL, Cheong SK, Leong CF, Othman A
    Cytotherapy, 2008;10(2):116-24.
    PMID: 18368590 DOI: 10.1080/14653240701816996
    Mesenchymal stromal cells (MSC) are pluripotent progenitor cells that can be found in human bone marrow (BM). These cells have low immunogenicity and could suppress alloreactive T-cell responses. In the current study, MSC were tested for their capacity to carry and deliver the erythropoietin (EPO) gene in vitro.
    Matched MeSH terms: Pluripotent Stem Cells/cytology
  14. In vitro generation of functional insulin-producing cells from lipoaspirated human adipose tissue-derived stem cells
    Mohamad Buang ML, Seng HK, Chung LH, Saim AB, Idrus RB
    Arch Med Res, 2012 Jan;43(1):83-8.
    PMID: 22374243 DOI: 10.1016/j.arcmed.2012.01.012
    BACKGROUND AND AIMS: Tissue engineering strategy has been considered as an alternative treatment for diabetes mellitus due to lack of permanent pharmaceutical treatment and islet donors for transplantation. Various cell lines have been used to generate functional insulin-producing cells (IPCs) including progenitor pancreatic cell lines, embryonic stem cells (ESCs), umbilical cord blood stem cells (UCB-SCs), adult bone marrow stem cells (BMSCs), and adipose tissue-derived stem cells (ADSCs).

    METHODS: Human ADSCs from lipoaspirated abdominal fat tissue was differentiated into IPCs following a two-step induction protocol based on a combination of alternating high and low glucose, nicotinamide, activin A and glucagon-like peptide 1 (GLP-1) for a duration of 3 weeks. During differentiation, histomorphological changes of the stem cells towards pancreatic β-islet characteristics were observed via light microscope and transmission electron microscope (TEM). Dithizone (DTZ) staining, which is selective towards IPCs, was used to stain the new islet-like cells. Production of insulin hormone by the cells was analyzed via enzyme-linked immunosorbent assay (ELISA), whereas its hormonal regulation was tested via a glucose challenge test.

    RESULTS: Histomorphological changes of the differentiated cells were noted to resemble pancreatic β-cells, whereas DTZ staining positively stained the cells. The differentiated cells significantly produced human insulin as compared to the undifferentiated ADSCs, and its production was increased with an increase of glucose concentration in the culture medium.

    CONCLUSIONS: These initial data indicate that human lipoaspirated ADSCs have the potential to differentiate into functional IPCs, and could be used as a therapy to treat diabetes mellitus in the future.

    Matched MeSH terms: Induced Pluripotent Stem Cells/physiology*; Induced Pluripotent Stem Cells/ultrastructure
  15. Fulltext Incomplete cellular reprogramming of colorectal cancer cells elicits an epithelial/mesenchymal hybrid phenotype
    Hiew MSY, Cheng HP, Huang CJ, Chong KY, Cheong SK, Choo KB, et al.
    J Biomed Sci, 2018 Jul 19;25(1):57.
    PMID: 30025541 DOI: 10.1186/s12929-018-0461-1
    BACKGROUND: Induced pluripotency in cancer cells by ectopic expression of pluripotency-regulating factors may be used for disease modeling of cancers. MicroRNAs (miRNAs) are negative regulators of gene expression that play important role in reprogramming somatic cells. However, studies on the miRNA expression profile and the expression patterns of the mesenchymal-epithelial transition (MET)/epithelial-mesenchymal transition (EMT) genes in induced pluripotent cancer (iPC) cells are lacking.

    METHODS: iPC clones were generated from two colorectal cancer (CRC) cell lines by retroviral transduction of the Yamanaka factors. The iPC clones obtained were characterized by morphology, expression of pluripotency markers and the ability to undergo in vitro tri-lineage differentiation. Genome-wide miRNA profiles of the iPC cells were obtained by microarray analysis and bioinformatics interrogation. Gene expression was done by real-time RT-PCR and immuno-staining; MET/EMT protein levels were determined by western blot analysis.

    RESULTS: The CRC-iPC cells showed embryonic stem cell-like features and tri-lineage differentiation abilities. The spontaneously-differentiated post-iPC cells obtained were highly similar to the parental CRC cells. However, down-regulated pluripotency gene expression and failure to form teratoma indicated that the CRC-iPC cells had only attained partial pluripotency. The CRC-iPC cells shared similarities in the genome-wide miRNA expression profiles of both cancer and pluripotent embryonic stem cells. One hundred and two differentially-expressed miRNAs were identified in the CRC-iPC cells, which were predicted by bioinformatics analysis be closely involved in regulating cellular pluripotency and the expression of the MET/EMT genes, possibly via the phosphatidylinositol-3 kinases-protein kinase B (PI3K-Akt) and transforming growth factor beta (TGF-β) signaling pathways. Irregular and inconsistent expression patterns of the EMT vimentin and Snai1 and MET E-cadherin and occludin proteins were observed in the four CRC-iPC clones analyzed, which suggested an epithelial/mesenchymal hybrid phenotype in the partially reprogrammed CRC cells. MET/EMT gene expression was also generally reversed on re-differentiation, also suggesting epigenetic regulation.

    CONCLUSIONS: Our data support the elite model for cancer cell-reprogramming in which only a selected subset of cancer may be fully reprogrammed; partial cancer cell reprogramming may also elicit an epithelial-mesenchymal mixed phenotype, and highlight opportunities and challenges in cancer cell-reprogramming.

    Matched MeSH terms: Induced Pluripotent Stem Cells/metabolism; Induced Pluripotent Stem Cells/pathology
  16. Induced pluripotent stem cells (iPSCs): the emergence of a new champion in stem cell technology-driven biomedical applications
    Das AK, Pal R
    J Tissue Eng Regen Med, 2010 Aug;4(6):413-21.
    PMID: 20084623 DOI: 10.1002/term.258
    Pluripotent stem cells possess the unique property of differentiating into all other cell types of the human body. Further, the discovery of induced pluripotent stem cells (iPSCs) in 2006 has opened up new avenues in clinical medicine. In simple language, iPSCs are nothing but somatic cells reprogrammed genetically to exhibit pluripotent characteristics. This process utilizes retroviruses/lentiviruses/adenovirus/plasmids to incorporate candidate genes into somatic cells isolated from any part of the human body. It is also possible to develop disease-specific iPSCs which are most likely to revolutionize research in respect to the pathophysiology of most debilitating diseases, as these can be mimicked ex vivo in the laboratory. These models can also be used to study the safety and efficacy of known drugs or potential drug candidates for a particular diseased condition, limiting the need for animal studies and considerably reducing the time and money required to develop new drugs. Recently, functional neurons, cardiomyocytes, pancreatic islet cells, hepatocytes and retinal cells have been derived from human iPSCs, thus re-confirming the pluripotency and differentiation capacity of these cells. These findings further open up the possibility of using iPSCs in cell replacement therapy for various degenerative disorders. In this review we highlight the development of iPSCs by different methods, their biological characteristics and their prospective applications in regenerative medicine and drug screening. We further discuss some practical limitations pertaining to this technology and how they can be averted for the betterment of human life.
    Matched MeSH terms: Induced Pluripotent Stem Cells/cytology*; Induced Pluripotent Stem Cells/metabolism
  17. Fulltext Induced pluripotent stem cells in research and therapy
    Teoh HK, Cheong SK
    Malays J Pathol, 2012 Jun;34(1):1-13.
    PMID: 22870592 MyJurnal
    Induced pluripotent stem cells (iPSC) are derived from human somatic cells through ectopic expression of transcription factors. This landmark discovery has been considered as a major development towards patient-specific iPSC for various biomedical applications. Unlimited self renewal capacity, pluripotency and ease of accessibility to donor tissues contribute to the versatility of iPSC. The therapeutic potential of iPSC in regenerative medicine, cell-based therapy, disease modelling and drug discovery is indeed very promising. Continuous progress in iPSC technology provides clearer understanding of disease pathogenesis and ultimately new optimism in developing treatment or cure for human diseases.
    Matched MeSH terms: Induced Pluripotent Stem Cells/cytology*; Induced Pluripotent Stem Cells/transplantation
  18. Fulltext Induced pluripotent stem cells: history, properties and potential applications
    Nordin N, Lai MI, Veerakumarasivam A, Ramasamy R, Abdullah S, Wendy-Yeo WY, et al.
    Med J Malaysia, 2011 Mar;66(1):4-9.
    PMID: 23765134 MyJurnal
    The development of induced pluripotent stem cells (iPSCs) has been met with much enthusiasm and hailed as a breakthrough discovery by the scientific and research communities amidst the divisive and ongoing debates surrounding human embryonic stem cells (hESC) research. The discovery reveals the fact that embryonic pluripotency can be generated from adult somatic cells by the induction of appropriate transcriptional factor genes essential for maintaining the pluripotency. They provide an alternative source for pluripotent stem cells, thus representing a powerful new research tool besides their potential application in the field of regenerative medicine. In this review, the historical background of iPSCs generation will be discussed together with their properties and characteristics as well as their potential therapeutic applications.
    Matched MeSH terms: Induced Pluripotent Stem Cells*
  19. Inherent differential propensity of dental pulp stem cells derived from human deciduous and permanent teeth
    Govindasamy V, Abdullah AN, Ronald VS, Musa S, Ab Aziz ZA, Zain RB, et al.
    J Endod, 2010 Sep;36(9):1504-15.
    PMID: 20728718 DOI: 10.1016/j.joen.2010.05.006
    Lately, several new stem cell sources and their effective isolation have been reported that claim to have potential for therapeutic applications. However, it is not yet clear which type of stem cell sources are most potent and best for targeted therapy. Lack of understanding of nature of these cells and their lineage-specific propensity might hinder their full potential. Therefore, understanding the gene expression profile that indicates their lineage-specific proclivity is fundamental to the development of successful cell-based therapies.
    Matched MeSH terms: Pluripotent Stem Cells/cytology; Pluripotent Stem Cells/physiology
  20. Lack of methylation on transgene leads to high level and persistent transgene expression in induced pluripotent stem cells
    Alhaji SY, Nordin N, Ngai SC, Al Abbar A, Mei L, Abdullah S
    Gene, 2020 Oct 20;758:144958.
    PMID: 32683073 DOI: 10.1016/j.gene.2020.144958
    Short-lived therapeutic gene expression in mammalian cells by DNA methylation is one of the major challenges in gene therapy. In this study, we assessed the implication of DNA methylation on the duration of GFP expression in mouse embryonic stem (ES) and mouse induced pluripotent stem (iPS) cells. The cells were transduced with lentivirus (LV) carrying green fluorescent protein (GFP) driven by either human elongation factor (EF1α) or cytomegalovirus (CMV) promoter. Transduced iPS cells exhibited higher percentage of GFP+ cells with persistent mean fluorescent intensity than transduced ES cells. Analysis on the integrated copy of transgene in the population of the transduced cells demonstrated similar copy number. However, significant increase in GFP intensity following 5-azaC treatment was observed in transduced ES cells only, suggesting the influence of DNA methylation in transgene silencing. Subsequent DNA methylation analysis showed that the promoter and the GFP region of the provirus in iPS cells had negligible methylation profile compared to transduced ES cells. Interestingly, sustained transgene expression was observed upon directed differentiation of transduced iPS cells towards CD34+ CD45+ cells. Hence, this study has shown that favourable transgene activity from lentiviral transduced iPS cells was due to the lack of methylation at the proviral regions.
    Matched MeSH terms: Induced Pluripotent Stem Cells/metabolism*
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